Towards realistic mobility models for mobile ad hoc networks

Abstract

One of the most important methods for evaluating the characteristics of ad hoc networking protocols is through the use of simulation. Simulation provides researchers with a number of significant benefits, including repeatable scenarios, isolation of parameters, and exploration of a variety of metrics. The topology and movement of the nodes in the simulation are key factors in the performance of the network protocol under study. Once the nodes have been initially distributed, the mobility model dictates the movement of the nodes within the network. Because the mobility of the nodes directly impacts the performance of the protocols, simulation results obtained with unrealistic movement models may not correctly reflect the true performance of the protocols. The majority of existing mobility models for ad hoc networks do not provide realistic movement scenarios; they are limited to random walk models without any obstacles. In this paper, we propose to create more realistic movement models through the incorporation of obstacles. These obstacles are utilized to both restrict node movement as well as wireless transmissions. In addition to the inclusion of obstacles, we construct movement paths using the Voronoi diagram of obstacle vertices. Nodes can then be randomly distributed across the paths, and can use shortest path route computations to destinations at randomly chosen obstacles. Simulation results show that the use of obstacles and pathways has a significant impact on the performance of ad hoc network protocols.

Real-world environment models for mobile network evaluation

“…Exponentially distributed destination selection: In our earlier model [19], we indicated that a node selects a destination randomly and then moves to that point by computing the shortest path. This selection method follows a uniform distribution, i.e., the probability with which a node selects a destination is independent of its distance to the destination.…”

“…In our previous work [19], we assumed that walls of building were thick enough to block any transmission that passes through them. In that case, two nodes located on opposite sides of one or more walls would not be able to communicate with each other.…”

“…Previous research [8], [19] has shown that the mobility model used can significantly impact the performance of ad hoc routing protocols, including the packet delivery ratio, the control overhead, and the data packet delay. Hence, it is important to use mobility models that accurately represent the intended scenarios in which the protocol is likely to be utilized.…”

“…Our goal in this paper is to extend our previous work [19] and create a fully developed real-world model. To this extent, we have augmented the model with additional features including, most importantly, movement heuristics and realistic signal fading.…”

Perfect Simulations for Random Trip Mobility Models

“…Recently though, various mobility models have been proposed which attempt to better capture mobility traces than RWM. These mobility models range from Obstacle Mobility Model [2] to City Section Mobility models (see the survey [3]). …”